Polymer for organic anti-reflective coating layer and composition including the same

ABSTRACT

A polymer which has siloxane group at a main chain thereof and a composition including the same, for forming an organic anti-reflective coating layer are disclosed. The polymer for forming an organic anti-reflective coating layer is represented by following Formula. 
     
       
         
         
             
             
         
       
     
     In Formula, R is hydrogen atom, C 1 ˜C 20  alkyl group, C 1 ˜C 10  alcohol group or epoxy group, R 1  is independently hydrogen atom, 
                         
n is an integer of 1-50, R 2  is C 1 ˜C 20  alkyl group, C 3 ˜C 20  cycloalkyl group, C 6 ˜C 20  aryl group or C 7 ˜C 12  arylalkyl group, R 3  is hydrogen atom, C 1 ˜C 10  alcohol group or epoxy group and POSS is a polyhedral oligosilsesquioxane.

This application claims the priority benefit of Korean PatentApplication No. 10-2006-0132668 filed on Dec. 22, 2006. All disclosureof the Korean Patent application is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to a polymer for forming an organicanti-reflective coating layer and a composition comprising the same, andmore specifically to a polymer for forming an organic anti-reflectivecoating layer, which has siloxane group at a main chain thereof, and acomposition comprising the same.

BACKGROUNDS OF THE INVENTION

Recently, as the integration degree increase, ArF(193 nm) excimer laserof short wavelength is used as the exposure light source in order toimprove the resolution of the photoresist pattern. However, as thewavelength of the exposure light is shorter, optical interference of thelight reflected from the etching layer of the semi-conductor substrateduring the exposure process, increases. In addition, due toundercutting, notching, etc., the photoresist pattern profile and theuniformity of thickness are deteriorated. To overcome these problems,the bottom anti-reflective coating (BARC) layer is conventionally formedbetween the etching layer and the photoresist layer to absorb theexposure light. The anti-reflective coating layer can be classified intothe inorganic anti-reflective coating layer made of titanium, titaniumdioxide, titanium nitride, chrome oxide, carbon, amorphous silicon, andso on, and the organic anti-reflective coating layer made of a polymer,which depends on the material for forming the anti-reflected coatinglayer. In comparison with the inorganic layer, the organicanti-reflective coating layer does not generally require complex andexpensive apparatus such as a vacuum deposition equipment, a chemicalvapor deposition (CVD) device, a sputter device and so on for formingthe layer, and has a high absorptivity of a radioactive light, and isgenerally insoluble in a photoresist solvent. Also, even small materialsthereof does not diffuse from the anti-reflective coating layer into aphotoresist layer during coating, heating, and drying the photoresistlayer, and the organic anti-reflective coating layer has an excellentetch rate in a dry etch process of a photolithography process. But untilnow, in the photolithography process using various radiations includingArF etc., the conventional composition for forming the organicanti-reflective coating layer is not satisfactory in itscharacteristics, such as the absorptivity of an exposure light.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide a polymerfor forming an anti-reflective coating layer and a composition includingthe same, which have improved etch rate and refractive Index and preventthe undercutting and notching in the photolithography process which usesvarious radiations including ArF as exposure light source.

To accomplish the object, the present invention provides a polymer forforming an anti-reflective coating layer, represented by followingFormula 1.

In Formula 1, R is hydrogen atom, C₁˜C₂₀ alkyl group, C₁˜C₁₀ alcoholgroup or epoxy group. R₁ is independently hydrogen atom,

and n is an integer of 1-50. R₂ is C₁˜C₂₀ alkyl group, C₃˜C₂₀ cycloalkylgroup, C₆˜C₂₀ aryl group or C₇˜C₁₂ arylalkyl group. R₃ is hydrogen atom,C₁˜C₁₀ alcohol group or epoxy group and POSS is a polyhedraloligosilsesquioxane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates GPC (Gel permeation chromatography) analysis graph ofpolymer for forming an organic anti-reflective coating layer which ismanufactured according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A more complete appreciation of the invention, and many of the attendantadvantages thereof, will be better appreciated by reference to thefollowing detailed description.

A polymer for forming an organic anti-reflective coating layer accordingto the present invention is represented by following Formula 1.

In Formula 1, R is hydrogen atom, C₁˜C₂₀ alkyl group, C₁˜C₁₀ alcoholgroup or epoxy group. R₁ is independently hydrogen atom,

and n is an integer of 1-50. R₂ is C₁˜C₂₀ alkyl group, C₃-C₂₀ cycloalkylgroup, C₆˜C₂₀ aryl group or C₇˜C₁₂ arylalkyl group. R₃ is hydrogen atom,C₁˜C₁₀ alcohol group or epoxy group, preferably hydrogen atom,propan-1-ol, butan-2-ol or 2-ethyl-oxirane. POSS is a three-dimensionalmolecular structure containing siloxane chains composed of Si/O groupsand a structural formula thereof is (SiO_(1.5))_(x)R_(x-1)

wherein x is 8, 10 or 12, R is H, OH, C₁˜C₂₀ alkyl group, alkene group,alkyne group, aryl group or alkoxyl group and the symbol

indicates a connecting bond. Specific examples of the POSS include

in which x is 8. Molecular weight of POSS used in the present inventionis preferably 700 to 2550. Preferable example of polymers for forming anorganic anti-reflective coating layer is a compound represented byfollowing Formula 2.

In Formula 2, R is as defined in Formula 1, preferably methyl group, R₂is as defined as Formula 1, a and b independently represent mol % ofrepeating units constituting the polymer and are 1˜99 mol % and 1˜99 mol%.

Also, preferable example of compound of Formula 1 includes a compoundrepresented by following Formula 3.

In Formula 3, R is as defined in Formula 1, preferably methyl group. R₂and R₃ are as defined in Formula 1 and a, b and c independentlyrepresent mol % of repeating units constituting the polymer and are 1˜98mol %, 1˜98 mol % and 1-98 mol %.

The weight-average molecular weight of the polymer represented byFormula 2 and Formula 3 is preferably 1,000 to 100,000. If the molecularweight is less than 1,000, the organic anti-reflective coating layer canbe dissolved by a photoresist solvent. If the molecular weight is morethan 100,000, a solubility of the polymer to a solvent might decrease,and the etch rate of the organic anti-reflective coating layer in a dryetch process might decrease.

The polymer represented by Formula 1 to Formula 3 has siloxane group atits main chain. Thus, the etch rate of the organic anti-reflectivecoating layer is improved and the organic anti-reflective coating layerhas high refractive index which is very essential to the organicanti-reflective coating layer. The high refractive index decreases thethickness of the organic anti-reflective coating layer. Also, therepeating unit b of the polymer represented by Formula 2 has POSS group,so the organic anti-reflective coating layer has high refractive index.The repeating unit c of the polymer represented by Formula 3 hashydroxyl group or epoxy group which promotes cross-linking in hardening,so the cross-linking density is increased and the refractive index isimproved.

At need, the polymer for forming an organic anti-reflective coatinglayer according to the present invention further includes a polymer of across-linking accelerator, represented by following Formula 4.

In Formula 4, m is an integer of 2 to 200. The polymer represented byFormula 4 contains phenyl group, so absorptivity to light at a specifiedwavelength region (193 nm) is very excellent to prevent non-uniformreflection. Since the polymer represented by Formula 4 contains hydroxylgroup, cross-linking by the heating can be accelerated.

The polymer for forming an organic anti-reflective coating layeraccording to the present invention can be manufactured by theconventional polymerization, for example addition polymerization asshown in following Reaction Equation 1.

In Reaction Equation 1 firstly poly(methylhydrosiloxane) andPOSS-ethylmethacrylate are added to an organic solvent, and reaction isperformed at 90° C. under chloroplatinic acid (H₂PtCl) catalyst toobtain polymer represented by Formula 2a. Next, the organic solvent andhydroxy ethyl methacrylate are added to the obtained polymer and thereaction is performed at 90° C. under H₂PtCl catalyst to obtain polymerrepresented by Formula 3a.

The composition for forming an organic anti-reflective coating layeraccording to the present invention includes a polymer represented byFormula 1, 2 or 3, a light absorber and a solvent. The composition forforming the organic anti-reflective coating layer according to thepresent invention can further include the second organic polymer whichimproves the coating characteristic of the composition, and can be curedby heating to increase the adhesion property of the organicanti-reflective coating layer. The non-limiting examples of such organicpolymer include polymer or co-polymer of acrylate, methacrylate,styrene, hydroxy styrene, oxyalkylene, oxymethylene, amide, imide,ester, ether, vinylacetate, vinylether methyl, vinylether-malericanhydride, and urethance. Other non-limiting examples include phenolicresin, epoxy resin, novolac resin, and the mixtures thereof.

The light absorber is to absorb various exposure light such as ArF(193nm) which is reflected from an etching layer in a photolithographyprocess, and thereby to prevent the problems such as a undercutting, anotching which may occur in a photoresist pattern. As the light absorberuseful in the present invention, various conventional light absorberscan be used. The representative example of the light absorber can berepresented by the following Formula 5, which is disclosed in KoreanPatent Application No. 2004-76011, the content of which is included inthis specification for reference.

In Formula 5, R₁ to R₉ are independently hydrogen atom, hydroxyl group,halogen atom, nitro group, amino group, C₁˜C₈ alkyl group with orwithout hydroxyl group, C₁˜C₈ alkoxy group with or without carbonylgroup, phenyl group, C₅˜C₁₀ cycloalkyl group, aryl-alkyl group,alkyl-aryl group, and at least one of R₁ to R₉ is not hydrogen atom.Preferable example of compound represented by Formula 5 includes

The amount of the light absorber is preferably 0.1 to 30 weight % withrespect to the total amount of the composition for forming the organicanti-reflective coating layer. If the amount is less than 0.1 weight %,the undercutting and the notching in a photoresist pattern can begenerated due to the low absorptivity of light reflected from thesubstrate of a semi-conductor. If the amount is more than 30 weight %,the coating apparatus can be spoiled due to the generation of fumes in aheating process. Also, due to the bulky structure of the light absorber,the organic anti-reflective coating layer does not contractedexcessively. The light absorber also works as a plasticizer, whichassists the composition's uniform coating even on a curved substrate. Inaddition, the light absorber has a good compatibility with a highmolecular weight material such as a polymer, and has an excellentsolubility to a solvent for forming the organic anti-reflective coatinglayer, and has a good reactivity with a cross-linking agent.Accordingly, a loss of thickness which may occur by a photoresistsolvent can be prevented. The light absorber has an excellentabsorptivity for an exposure light from ArF excimer laser, and therebythe light absorber can be effectively used for a semi-conductorsubstrate having a high reflectivity.

As the solvent, which is a component of the composition for forming theorganic anti-reflective coating layer according to the preventinvention, various solvents which can conventionally used formanufacturing the composition for forming the organic anti-reflectivecoating layer can be widely used. The unlimited example of solventincludes butyrolactone, cyclopentanon, cyclohexanon, dimethyl acetamide,dimethyl formamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofurfural alcohol, propyleneglycol monomethylether(PGME), propyleneglycolmonomethylether acetate(PGMEA), ethylactate and the mixtures thereof,and the more preferable solvent includes propyleneglycolmonomethylether, propyleneglycol monomethylether acetate(PGMEA),ethylactate and the mixtures thereof. The amount of the solvent ispreferably 40 to 99.8 weight % with respect to the total amount of thecomposition for forming the organic anti-reflective coating layer. Ifthe amount is less than 40 weight %, the thickness of the organicanti-reflective coating layer may become non-uniform. If the amount ismore than 99.8 weight %, the physical characteristic of the formedorganic anti-reflective coating layer such as the absorbance of anexposure light may be deteriorated.

Also, the composition for forming the organic anti-reflective coatinglayer according to the present invention may further include across-linking accelerator such as a cross-linking agent, a low molecularweight alcohol, an acid, or an acid generator, a leveling agent, anadhesion promoter, an anti-foaming agent, and other various additives.

To form the organic anti-reflective coating layer with the compositionof the present invention, the composition for forming the organicanti-reflective coating layer is applied on an etching layer, and theapplied composition is cured by heating. The process of applying thecomposition for forming the organic anti-reflective coating layer iscarried out by a conventional method such as spin coating, rollercoating and so on. Also, the curing process is carried out by heatingthe applied composition in an apparatus such as a high-temperatureplate, a convection oven, and so on. The curing process can bepreferably carried out at high temperature, so that the cured organicanti-reflective coating layer may not be dissolved in an organic solventof a photoresist composition or an aqueous alkaline developer. Thepreferable temperature of the curing process is 70° C. to 240° C. If thecuring temperature is less than 70° C., the solvent included in thecomposition for forming the organic anti-reflective coating layer can benot removed sufficiently, and the cross-linking reaction can be notcarried out sufficiently. If the curing temperature is more than 240°C., the organic anti-reflective coating layer and the composition forforming the same might become chemically unstable.

The method for forming a semi-conductor element pattern by using thecomposition for forming the organic anti-reflective coating layeraccording to the present invention comprises the steps of: applying thecomposition for forming the organic anti-reflective coating layer on anetching layer; forming the organic anti-reflective coating layer bycuring, for example, by heat-curing the composition applied on theetching layer; forming a photoresist pattern by applying a photoresistcomposition on the organic anti-reflective coating layer to form aphotoresist layer, exposing the photoresist layer to an exposure lightof a predetermined pattern, and developing the exposed photoresistlayer; and forming an etching pattern by etching the organicanti-reflective coating layer and the etching layer by using the formedphotoresist pattern as a mask. Here, the process of forming the organicanti-reflective coating layer is described above. The photoresistpattern forming step is a conventional process and can be easily carriedout by a skilled person in the art according to the photoresistcomposition. For example, the photoresist composition is applied orcoated on the organic anti-reflective coating layer by a conventionalmethod such as spin-coating, and the photoresist layer can be exposed toan exposure light through a photo-mask of a predetermined pattern. Also,the process of forming the photoresist pattern can include the step ofbaking the photoresist layer before or after the light exposing process,and the preferable baking temperature is 70° C. to 150° C. If the bakingtemperature is less than 70° C., the organic solvent in the photoresistcomposition may not be sufficiently evaporated and it is impossible toform the pattern because the PAG is sufficiently not diffused. If thebaking temperature is more than 150° C., the diffusion of PAG isextremely active, so desired pattern cannot be obtained and thephotoresist composition might be chemically unstable. The developingprocess can be carried out by using a conventional aqueous developer,and for example, by using the 0.1 to 10 weight % of sodium hydroxide,potassium hydroxide, sodium carbonate or TMAH (tetramethyl ammoniumhydroxide) solution. The aqueous organic solvent such as methanol orethanol etc, and surfactant are added to the developer. Also, afterdeveloping process, the exposed photoresist pattern is washed withpurified water. Finally, the organic anti-reflective coating layer andthe etching layer are etched by using the formed photoresist pattern asa mask to form the etching layer pattern. The etching process can becarried out by a conventional dry etching process. The semi-conductorelement pattern is formed by etching the organic anti-reflective coatinglayer and the etching layer.

Hereinafter, the preferable examples are provided for betterunderstanding of the present invention. However, the present inventionis not limited to the following examples. POSS used in followingexamples was

(R is methyl group (CH₃)).

EXAMPLE 1-1 Preparation of Polymer Represented by Formula 2a

30 g (0.0333 mol) of poly(methylhydrosiloxane) (item no-176206 ofAldrich company) and 1 l of toluene and 5 g (0.00549 mol) of compoundrepresented by Formula 1a were added into 2 l reactor in which amagnetic stirring rod was provided, and the reaction solution was heatedto 90° C. Next, 50 μl of H₂PtCl (catalyst) was slowly added to thereaction solution and the reaction was performed for 24 hours. After thecompletion of the reaction, the product from the reaction wasprecipitated by water and filtered and then the filtered was dissolvedin tetrahydrofurane(THF). To remove residual H₂PtCl, column wasproceeded to finally obtain 20 g of polymer represented by followingFormula 2a with 57% yield (a:b=80:20, Mw=12,500, PD=1.78).

EXAMPLE 1-2 Preparation of Polymer Represented by Formula 2b

Except for using 5 g (0.00518 mol) of compound in Formula 1b instead of5 g of compound in Formula 1a, 18 g of polymer represented by Formula 2bwas prepared with yield 51% in the same manner described in Example 1-1(a:b=78:22, Mw=12,500, PD=1.76).

EXAMPLE 1-3 Preparation of Polymer Represented by Formula 2c

Except for using 5 g (0.00521 mol) of compound in Formula 1c instead of5 g of compound in Formula 1a, 22 g of polymer represented by Formula 2cwas prepared with yield 63% in the same manner described in Example 1-1(a:b=75:25, Mw=11,900, PD=1.77).

EXAMPLE 1-4 Preparation of Polymer Represented by Formula 2d

Except for using 5 g (0.00477 mol) of compound in Formula 1d instead of5 g of compound in Formula 1a, 19 g of polymer represented by Formula 2dwas prepared with yield 54% in the same manner described in Example 1-1(a:b=82:18, Mw=10,800, PD=1.80).

EXAMPLE 1-5 Preparation of Polymer Represented by Formula 2e

Except for using 5 g (0.00483 mol) of compound in Formula 1e instead of5 g of compound in Formula 1a, 15 g of polymer represented by Formula 2ewas prepared with yield 43% in the same manner described in Example 1-1(a:b=80:20, Mw=12,200, PD=1.75).

EXAMPLE 1-6 Preparation of Polymer Represented by Formula 2f

Except for using 5 g (0.00489 mol) of compound in Formula 1f instead of5 g of compound in Formula 1a, 21 g of polymer represented by Formula 2fwas prepared with yield 60% in the same manner described in Example 1-1(a:b=78:22, Mw=9,900, PD=1.74).

EXAMPLE 1-7 Preparation of Polymer Represented by Formula 2g

Except for using 5 g (0.00492 mol) of compound in Formula 1g instead of5 g of compound in Formula 1a, 20 g of polymer represented by Formula 2gwas prepared with yield 57% in the same manner described in Example 1-1(a:b=75:25, Mw=11,500, PD=1.80).

EXAMPLE 1-8 Preparation of Polymer Represented by Formula 2 h

Except for using 5 g (0.00453 mol) of compound in Formula 1 h instead of5 g of compound in Formula 1a, 18 g of polymer represented by Formula 2h was prepared with yield 51% in the same manner described in Example1-1 (a:b=83:17, Mw=10,200, PD=1.79).

EXAMPLE 1-9 Preparation of Polymer Represented by Formula 2i

Except for using 5 g (0.0060 mol) of compound in Formula 1i instead of 5g of compound in Formula 1a, 19 g of polymer represented by Formula 21was prepared with yield 54% in the same manner described in Example 1-1(a:b=80:20, Mw=11,500, PD=1.75).

EXAMPLE 2-1 Preparation of Polymer Represented by Formula 3a

20 g of polymer (Formula 2a) obtained in Example 1-1, 1 l of toluene and10 g (0.077 mol) of hydroxy ethyl methacrylate were added into 2 lreactor in which a magnetic stirring rod was provided, and the reactionsolution was heated to 90° C. Next, 50 μl of H₂PtCl (catalyst) wasslowly added to the reaction solution and the reaction was performed for24 hours. After the completion of the reaction, the product from thereaction was precipitated by water and filtered and then the filteredwas dissolved in tetrahydrofurane(THF). To remove residual H₂PtCl,column was proceeded to finally obtain 18 g of polymer represented byfollowing Formula 3a with 80% yield. The weight-average molecular weight(Mw) and polydispersity (PDI) of the produced polymer were measured byGPC (Gel Permeation Chromatography) and the results are shown in thefollowing Table 1 (Mw=11,600, PD=1.62).

EXAMPLE 2-2 Preparation of Polymer Represented by Formula 3b

Except for using 20 g of polymer in Formula 2b and 10 g (0.069 mol) of2-hydroxy-propyl methacrylate instead of 20 g of polymer in Formula 2aand 10 g of hydroxy ethyl methacrylate, 22.5 g of polymer represented byFormula 3b was prepared with yield 75% in the same manner described inExample 2-1 (Mw=11,500, PD=1.82).

EXAMPLE 2-3 Preparation of Polymer Represented by Formula 3c

Except for using 20 g of polymer in Formula 2c and 10 g (0.078 mol) ofepoxy methacrylate instead of 20 g of polymer in Formula 2a and 10 g ofhydroxy ethyl methacrylate, 20.7 g of polymer represented by Formula 3cwas prepared with yield 69% in the same manner described in Example 2-1(Mw=10,200, PD=1.68).

EXAMPLE 2-4 Preparation of Polymer Represented by Formula 3d

Except for using 20 g of polymer in Formula 2d instead of 20 g ofpolymer in Formula 2a, 22.5 g of polymer represented by Formula 3d wasprepared with yield 75% in the same manner described in Example 2-1(Mw-9,800, PD=1.77).

EXAMPLE 2-5 Preparation of Polymer Represented by Formula 3e

Except for using 20 g of polymer in Formula 2e and 10 g (0.069 mol) of2-hydroxy-propyl methacrylate instead of 20 g of polymer in Formula 2aand 10 g of hydroxy ethyl methacrylate, 19.8 g of polymer represented byFormula 3e was prepared with yield 66% in the same manner described inExample 2-1 (Mw=9,600, PD=1.86).

EXAMPLE 2-6 Preparation of Polymer Represented by Formula 3f

Except for using 20 g of polymer in Formula 2f and 10 g (0.078 mol) ofepoxy methacrylate instead of 20 g of polymer in Formula 2a and 10 g ofhydroxy ethyl methacrylate, 21.6 g of polymer represented by Formula 3fwas prepared with yield 72% in the same manner described in Example 2-1(Mw=10,500, PD=1.86).

EXAMPLE 2-7 Preparation of Polymer Represented by Formula 3g

Except for using 20 g of polymer in Formula 2g instead of 20 g ofpolymer in Formula 2a, 19.5 g of polymer represented by Formula 3g wasprepared with yield 65% in the same manner described in Example 2-1(Mw=11,200, PD=1.69).

EXAMPLE 2-8 Preparation of Polymer Represented by Formula 3h

Except for using 20 g of polymer in Formula 2h and 10 g (0.069 mol) of2-hydroxy-propyl methacrylate instead of 20 g of polymer in Formula 2aand 10 g of hydroxy ethyl methacrylate, 21 g of polymer represented byFormula 3h was prepared with yield 70% in the same manner described inExample 2-1 (Mw=10,900, PD=1.73).

EXAMPLE 2-9 Preparation of Polymer Represented by Formula 3i

Except for using 20 g of polymer in Formula 2i and 10 g (0.078 mol) ofepoxy methacrylate instead of 20 g of polymer in Formula 2a and 10 g ofhydroxy ethyl methacrylate, 21.9 g of polymer represented by Formula 31was prepared with yield 73% in the same manner described in Example 2-1(Mw=9,900, PD=1.85).

EXAMPLE 2-10 Preparation of Polymer Represented by Formula 3j

Except for using 20 g of polymer in Formula 2c and 10 g (0.069 mol) of2-hydroxy-propyl methacrylate instead of 20 g of polymer in Formula 2aand 10 g of hydroxy ethyl methacrylate, 21.3 g of polymer represented byFormula 3j was prepared with yield 71% in the same manner described inExample 2-1 (Mw=12,500, PD=1.88).

EXAMPLE 3-1 TO EXAMPLE 3-10 Preparation of Composition for Forming anOrganic Anti-Reflective Coating Layer Containing One of PolymersManufactured in Example 2-1 to Example 2-10

0.13 g of one of polymers (Formula 3a to Formula 3j) manufactured inExample 2-1 to Example 2-10, 0.091 g of light absorber represented byFormula 5a, 0.06 g of polyvinyl phenol as an cross-linking agent and0.01 g of 2-hydroxyhexyl p-toluenesulfonate as an acid-generator weredissolved in 13.7 g of PGMEA (propylene glycol monomethyl etheracetate), and stirred to obtain compositions for forming the organicanti-reflective coating layer.

TEST EXAMPLE 1 Stripping Test of the Organic Anti-Reflective CoatingLayer

The respective composition for forming an organic anti-reflectivecoating layer prepared in Example 3-1 to Example 3-10 was uniformlyapplied on a silicon substrate with a thickness of 240 Å, and was curedat 240° C. for 90 seconds to form an organic anti-reflective coatinglayer. After measuring the thickness of the organic anti-reflectivecoating layer, the organic anti-reflective coating layer was dipped in arespective solvent of PGMEA, PGME, EL and nBA for 60 seconds. Next thesubstrate was spin with the spinning speed of 2000 rpm for 30 secondsand dried at the heating-plate at 100° C. for 60 seconds. Then thethickness of the organic anti-reflective coating layer was measuredagain and the results thereof are shown in Table 1. Also, the refractiveindex (n) and the absorptivity (k) at 193 nm were measured by usingEllipsometer and the results thereof are shown in Table 1.

TABLE 1 Film Loss(with respect to n K respective solvent) Example 3-1(Formula 3a) 1.65 0.42 None Example 3-2 (Formula 3b) 1.60 0.50 NoneExample 3-3 (Formula 3c) 1.58 0.52 None Example 3-4 (Formula 3d) 1.650.49 None Example 3-5 (Formula 3e) 1.68 0.50 None Example 3-6 (Formula3f) 1.69 0.40 None Example 3-7 (Formula 3g) 1.65 0.48 None Example 3-8(Formula 3h) 1.69 0.53 None Example 3-9 (Formula 3i) 1.69 0.49 NoneExample 3-10 (Formula 3j) 1.58 0.43 None n: real part(refractive indexat 193 nm) K: imaginary part(absorptivity at 193 nm)

As shown in Table 1, the composition for forming an organicanti-reflective coating layer has no loss in view of thickness as wellas good refractive index and absorptivity. Thus the stripping-resistancethereof is superior.

In general, when k is less than a certain value (k<0.3) at a givenwavelength, the absorptivity is decreased, and the undercutting and thenotching, etc can be generated due to the non-uniform reflection. Thus,the photoresist pattern profile is deteriorated. On the contrary, when kis more than a certain value (for example, k>0.7), the absorptivityexcessively increases, and the sensitivity of photoresist may bedeteriorated. Thus, the throughput of the semiconductor production canbe deteriorated. As n increases (for example, n>1.8), the thickness ofthe organic anti-reflective coating layer can be reduced. So theresolution of 45 nm pattern which is finer than L/S pattern size (65 nm)of currently possible resolution can be accomplished. Thus, thecomposition of the present invention is applicable to ArF immersionprocess. On the contrary, as n decreases (for example, n<1.4), thethickness of the organic anti-reflective coating layer should bethickened and there is a problem that the etch rate becomes very slow.

As shown described above, the polymer for forming an organicanti-reflective coating layer according to the present invention has ahigh absorptivity of an exposure light from ArF excimer laser, and thegeneration of standing wave, undercutting and notching can be preventedto obtain the uniform pattern profile. In addition, the polymer improvesthe etch rate and the adhesion property to a substrate. In thephotolithography process using various lasers including ArF(193 nm)excimer laser as the exposure light, the composition for forming anorganic anti-reflective coating layer contains the light absorber havinga high absorptivity of an exposure light. So, lower coating layer forimproving the adverse effects from the reflected exposure light can beformed, contraction stability and coating uniformity of the organicanti-reflective coating layer are improved, and the thickness loss ofthe layer due to a photoresist solvent is lowered.

1. A polymer for forming an anti-reflective coating layer, representedby following Formula 3:

in Formula 3, R is hydrogen atom, C₁˜C₂₀ alkyl group, C₁˜C₁₀ alcoholgroup or epoxy group, R₂ is C₁˜C₂₀ alkyl group, C₃˜C₂₀ cycloalkyl group,C₆˜C₂₀ aryl group or C₇˜C₁₂ arylalkyl group, R₃ is hydrogen atom, C₁˜C₁₀alcohol group or epoxy group and POSS is a polyhedraloligosilsesquioxane, a, b and c independently represent mol % ofrepeating units constituting the polymer and are 1˜98mol %, 1˜98mol %and 1˜98mol %.